2] injures the respiratory tract and has its greatest effect upon respiratory bronchioles
(Chauhan et al.
29,100-126) The term diffuse panbronchiolitis refers to its distribution in both lungs (diffuse) and the inflammatory involvement of all layers of the wall or respiratory bronchioles (pan).
Variably extensive and variably severe inflammatory and fibrotic changes caused by tobacco smoke that are found in the terminal bronchioles and respiratory bronchioles are termed, respectively, membranous bronchiolitis and respiratory bronchiolitis.
A morphologic grading scheme for membranous and respiratory bronchioles
1) The CAP criteria require "discrete foci of fibrosis in the walls of respiratory bronchioles
associated with accumulations of asbestos bodies in histological sections.
Intriguingly, these vessels reside in proximity to the respiratory bronchioles
, where the conducting zone, or anatomic dead space, transitions into the gas exchange region.
Species with branching respiratory bronchioles
between the terminal bronchiole and alveolar ducts have more complex acini.
In the original article of Myers et al, (1) the major pathologic finding was the presence of RB: clusters of slightly golden colored alveolar macrophages ("smoker's macrophages") in the lumens of respiratory bronchioles
, alveolar ducts, and in the surrounding alveoli.
The 19th, 20th, and 21st are called respiratory bronchioles
and are different from preceding bronchioles in that their epithelium changes form pseudostratified ciliated columnar to squamus, nonciliated.
In contrast, terminal and respiratory bronchioles
arising from each pathway revealed varying degrees of wall thickening and remodeling.
The stellate lesions are small, discrete, and centered around respiratory bronchioles
and adjacent small arteries, with intervening uninvolved lung parenchyma present.
We also describe the surprising finding of fibrotic lesions of the large bronchi, which is usually restricted to membranous and respiratory bronchioles
, in the context of chronic rejection with OB.